Fuel injection? Open or Closed loop?

[cmracing]

Originally Posted by Ed Wright

Depends. Usually more in cool weather. In my case, FAST XFI (with the straight line across the Manifold Air Temp correction table/"map"), "compensated" a little too much. (Added just a little too much fuel in lower temps, etc) It would take somebody much sharper than myself to simply dyno tune one on a given day to get that part dialed in right. I guess some dyno rooms could have the inlet air temps adjusted that much?
I have to do it the hard way.

Same here. About 23/24* drop in cool weather, 18/20* in hot/humid weather. But, this is in a Bracket Car with a cowl hoodscoop and an air pan sealed to the hood.

I do very little compensation for air temp, in fact, in the range it is in for racing it does nothing. When its really cold (below 50*) I add 2% just to help it. We don't race in that cold of weather though.

Same thing for coolant temp. Below 80* I add fuel to help with warmup, but above 80*, no change.

It is interesting Robin mentioned not using the Learn function once the engine is tuned. I still use it, but it is severely limited in what I let it do. I may as well turn it off and just let the Closed Loop take care of things but still limit it's range like present, +-2%.